BY1 WJEC cell division

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  • Created by: rosie25
  • Created on: 25-03-14 13:17
What are chromosomes made of?
DNA, protein and small amount of RNA
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When are chromosomes visible?
Just before cell division
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What is a section of DNA called?
a gene
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What is a nucleotide made up of?
A phosphate group, a pentose sugar, an organic base
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What are the 4 bases in DNA?
adenine, guanine, thymine and cytosine
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What does adenine pair with?
Guanine
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What does thymine pair with?
cytosine
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What is DNA?
a double-stranded polymer of nucleotides
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In DNA what is the pentose sugar?
Deoxyribose
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What are the bases joined together by?
Hydrogen bonds
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What is RNA?
a single-stranded polymer of nucleotide
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What sugar does RNA contain?
ribose
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What are the 4 bases?
Adenine, guanine, cytosine and URACIL
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What are the 3 types of RNA?
Messenger RNA, Ribosomal RNA, Transfer RNA
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What does mitosis produce?
2 daughter cells that are genetically identical
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What are the 5 stages of the cell cycle?
Interphase, prophase, metaphase, anaphase, telaphase
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What happens in interphase?
Longest stage. DNA is replicated. Just before division the chromosomes replicate- so each consists of 2 chromatids join togehter in centromere
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What happens in prophase?
First stage in mitosis. The chromosomes condense and become visible. Centrioles divide and move to opposite ends of cell. Spindle develops from centriole. Nuclear membrane disappears, chromatids can be seen.
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What happens in metaphase?
Chromosomes arrange themselves at centre and become attached to spindles at centromere
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What happens in anaphase?
Centromere splits and spindle contracts and pull the chromatids to poles and seperate.
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What happens in telophase?
Chromosomes uncil and lengthen. Spindles break down and centrioles replicate.
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What is the significance of mitosis?
Replicates cells- genetically identical so stable. Growth and repair. Asexual reproduction.
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What is meiosis?
Sexual reproduction. Two gametes fuse to form a zygote. For each generation to have a full set of chromosomes (diplod) the chromosomes must be halved (haploid)
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What happens in meiosis 1?
Chromosome number is halved
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What happens in meiosis 2?
Haploid nuclei divide again in a division identical to mitosis
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What does it result in?
4 daughter nuclei, each with half the number of chromosomes of parent cell.
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What is the difference between prophase in meiosis and mitosis?
In meiosis, homologous chromatids wrap around eachother and then partially repel eachother but remain joined at certain points. At these points the chromatids may break and recombine with a different chromatid. This is a source of genetic variation.
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Other cards in this set

Card 2

Front

When are chromosomes visible?

Back

Just before cell division

Card 3

Front

What is a section of DNA called?

Back

Preview of the front of card 3

Card 4

Front

What is a nucleotide made up of?

Back

Preview of the front of card 4

Card 5

Front

What are the 4 bases in DNA?

Back

Preview of the front of card 5
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Comments

TayaMairead

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Some questions are a bit ambiguous, but useful non the less :) 

TonyChenAspirations

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adenine does not pair up with guanine but with thymine

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